The Cat Mate Elite Select Cat Flap includes 2 electronic I.D. Discs (up to 7 unique I.D. Discs possible) to control entry and exit through the door - keeps all other animals out. LED display shows selected entry and exit lock status plus low battery indicator. Requires 4 x AA (R6) batteries. Self-lining up to 50mm (2") thick - ideal for all single/ double glazing and any panel 0 - 50mm (0 - 2") thick. Wall Liner available for wall installation. Fully draft and weatherproof brush sealed flap.